Various types of conveyors have been proposed for the food processing industry. Conveyors with a generally flat and unitary tray or pan floor are preferred from many applications since the product being conveyed contacts only the unitary tray, thereby contributing to easy cleaning and maintenance of the tray. Differential impulse conveyors are favored in many applications compared, for example, to vibratory conveyors because the product moving along the differential impulse tray is less susceptible to damage and to loss of seasoning from the product as it is transported along the conveyor.
One of the goals of a differential impulse conveyor for years has been to provide an assembly which reliably allows transported goods to be moved uphill. Uphill movement of the goods may be essential, for example, for downstream handling of the goods at the higher elevation. Current differential impulse conveyors with a flat tray floor can move goods up a slight incline in many applications, but frequently cannot move various types of goods up a substantial incline of, for example, six or eight degrees. A differential impulse conveyor with an uphill travel capability has long been desired to accommodate different food processing machine heights and/or to recirculate accumulated goods.
Another disadvantage of prior art differential impulse conveyors is the difficulty with determining the volume or the weight of the goods being transported. An accurate determination of the weight or the volume of the goods being transported is critical for many operations. During seasoning of goods, for example, the accurate determination of the weight of goods traveling past the conveyor at any point in time may be used to reliably adjust the seasoning rate applied to the product downstream from the conveyor. The weight of the goods on the tray is generally determined by a load cell on the conveyor which is responsive to the change in tray weight with the supported goods. This weight determination from the load cell may or may not be coupled with a product volume determination based on the sensed height of the goods being conveyed in a tray. Each of these measurements requires a determination of the travel rate of goods along the tray, and the travel rate of goods along a differential impulse conveyor tray is significantly affected by the changing height of the goods on the tray at any point in time. Accordingly, an accurate determination of the quantity of goods conveyed along the tray is lacking.
A differential impulse conveyor with a spiral tray for elevating goods moved along the tray is disclosed in U.S. Pat. No. 5,351,807. Another conveyor system involving a spiral drum engaging the outer edge of a belt is disclosed in U.S. Publication 2011/0056806. A special conveyor pan intended for use with base or gate conveyor is disclosed in U.S. Pat. No. 6,896,121. U.S. Pat. No. 3,960,266 uses a pusher bar to transfer goods from one conveyor to another conveyor. U.S. Pat. No. 3,901,375 discloses a product pusher on a belt conveyor. U.S. Pat. No. 6,189,683 discloses an improved drive for a differential impulse conveyor. A conveyor tray with dimples to eliminate excessive friction of products moving along a tray has been proposed by Gates Manufacturing.
The disadvantages of the prior art are overcome by the present invention, an improved differential impulse conveyor is hereinafter disclosed.